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String.Concat<T> Method (IEnumerable<T>)

Concatenates the members of an IEnumerable<T> implementation.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

[ComVisibleAttribute(false)]
public static string Concat<T>(
	IEnumerable<T> values
)

Type Parameters

T

The type of the members of values.

Parameters

values
Type: System.Collections.Generic.IEnumerable<T>

A collection object that implements the IEnumerable<T> interface.

Return Value

Type: System.String
The concatenated members in values.

ExceptionCondition
ArgumentNullException

values is null.

The method concatenates each object in values; it does not add any delimiters.

An Empty string is used in place of any null argument.

Concat<T>(IEnumerable<T>) is a convenience method that lets you concatenate each element in an IEnumerable<T> collection without first converting the elements to strings. It is particularly useful with Language-Integrated Query (LINQ) query expressions, as the example illustrates. The string representation of each object in the IEnumerable<T> collection is derived by calling that object's ToString method.

The following example defines a very simple Animal class that contains the name of an animal and the order to which it belongs. It then defines a List<T> object to contain a number of Animal objects. The Enumerable.Where extension method is called to extract the Animal objects whose Order property equals "Rodent". The result is passed to the Concat<T>(IEnumerable<T>) method and displayed to the console.

using System;
using System.Collections.Generic;
using System.Linq;

public class Animal
{
   public string Kind;
   public string Order;

   public Animal(string kind, string order)
   {
      this.Kind = kind;
      this.Order = order;
   }

   public override string ToString()
   {
      return this.Kind;
   }
}

public class Example
{
   public static void Main()
   {
      List<Animal> animals = new List<Animal>();
      animals.Add(new Animal("Squirrel", "Rodent"));
      animals.Add(new Animal("Gray Wolf", "Carnivora"));
      animals.Add(new Animal("Capybara", "Rodent"));
      string output = String.Concat(animals.Where( animal => 
                      (animal.Order == "Rodent")));
      Console.WriteLine(output);  
   }
}
// The example displays the following output: 
//      SquirrelCapybara

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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